fly/flightgear
1
0
Fork 0
Code Activity

Fixed arbitrary polygon winding problem here so all tristrips are passed

Browse source 
to runtime simulator with a consistant counter clockwise winding.
This commit is contained in:
curt 1998-05-20 20:55:18 +00:00
parent e30c10841c
commit f00f7f02d4
2 changed files with 121 additions and 19 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
FixObj/Makefile.in
View file

@ -347,8 +347,9 @@ INCLUDES += -I$(top_builddir) -I$(top_builddir)/Lib
#---------------------------------------------------------------------------
# $Log$
# Revision 1.12 1998/05/16 13:11:25 curt
# Fixed an off by one error in node, normal, and face counters.
# Revision 1.13 1998/05/20 20:55:18 curt
# Fixed arbitrary polygon winding problem here so all tristrips are passed
# to runtime simulator with a consistant counter clockwise winding.
#
# Revision 1.4 1998/04/24 00:44:05 curt
# Added zlib support.

135
FixObj/obj.c
View file

@ -71,13 +71,105 @@ void list_add(int *list, int *list_ptr, int node) {
}
/* fix the cw list and append to ccw_list */
void fix_cw_list(int *list, int list_ptr) {
int i, j, len;
if ( list_ptr < 3 ) {
printf("List is empty ... skipping\n");
return;
}
printf("Fixing cw list, size = %d\n", list_ptr);
i = 0;
while ( i < list_ptr ) {
/* do next strip */
/* find length */
len = 0;
/* scan rest of strip (until -1) */
while ( ((i+len) < list_ptr) && (list[i+len] != -1) ) {
// printf("len = %d item = %d\n", len, list[i+len] );
len++;
}
// printf(" Final length = %d\n", len);
if ( (len % 2) != 0 ) {
/* if length is odd, just reverse order of nodes to reverse
winding */
if ( ccw_list_ptr ) {
list_add(ccw_list, &ccw_list_ptr, -1);
}
for ( j = i + len - 1; j >= i; j-- ) {
// printf(" odd -> item = %d\n", list[j] );
list_add(ccw_list, &ccw_list_ptr, list[j]);
}
} else {
/* if length is even, reverse order of (n-1) nodes to
reverse winding, and create an orphan triangle for the
last "nth" node */
if ( ccw_list_ptr ) {
list_add(ccw_list, &ccw_list_ptr, -1);
}
for ( j = i + len - 2; j >= i; j-- ) {
// printf(" even -> item = %d\n", list[j] );
list_add(ccw_list, &ccw_list_ptr, list[j]);
}
// printf(" even bonus -> item = %d\n", list[i + len - 1] );
// printf(" even bonus -> item = %d\n", list[i + len - 2] );
// printf(" even bonus -> item = %d\n", list[i + len - 3] );
list_add(ccw_list, &ccw_list_ptr, -1);
list_add(ccw_list, &ccw_list_ptr, list[i + len - 3]);
list_add(ccw_list, &ccw_list_ptr, list[i + len - 2]);
list_add(ccw_list, &ccw_list_ptr, list[i + len - 1]);
}
i += len + 1;
}
}
// Calculate distance between (0,0,0) and the specified point
static double calc_dist(double x, double y, double z) {
return ( sqrt(x*x + y*y + z*z) );
}
void dump_global_bounds( void ) {
double dist, radius;
int i;
radius = 0.0;
fprintf(out, "\n");
for ( i = 1; i < ncount; i++ ) {
dist = calc_dist(nodes[i][0] - refx, nodes[i][1] - refy,
nodes[i][2] - refz);
// printf("node = %.2f %.2f %.2f dist = %.2f\n",
// nodes[i][0], nodes[i][1], nodes[i][2],
// dist);
if ( dist > radius ) {
radius = dist;
}
}
fprintf(out, "gb %.4f %.4f %.4f %.2f\n", refx, refy, refz, radius);
}
/* dump nodes */
void dump_nodes( void ) {
int i;
fprintf(out, "\n");
for ( i = 1; i <= ncount; i++ ) {
fprintf(out, "v %.4lf %.4lf %.4lf\n",
for ( i = 1; i < ncount; i++ ) {
fprintf(out, "v %.4f %.4f %.4f\n",
nodes[i][0] - refx, nodes[i][1] - refy, nodes[i][2] - refz);
}
}
@ -88,8 +180,8 @@ void dump_normals( void ) {
int i;
fprintf(out, "\n");
for ( i = 1; i <= vncount; i++ ) {
fprintf(out, "vn %.4lf %.4lf %.4lf\n",
for ( i = 1; i < vncount; i++ ) {
fprintf(out, "vn %.4f %.4f %.4f\n",
normals[i][0], normals[i][1], normals[i][2]);
}
}
@ -100,7 +192,7 @@ void dump_faces( void ) {
int i;
fprintf(out, "\n");
for ( i = 1; i <= fcount; i++ ) {
for ( i = 1; i < fcount; i++ ) {
fprintf(out, "f %d %d %d\n",
faces[i][0], faces[i][1], faces[i][2]);
}
@ -122,6 +214,12 @@ void dump_list(int *list, int list_ptr) {
while ( i < list_ptr ) {
/* do next strip */
if ( (i % 2) == 0 ) {
fprintf(out, "\nusemtl desert1\n");
} else {
fprintf(out, "\nusemtl desert2\n");
}
/* dump header */
fprintf(out, "t %d %d %d\n", list[i], list[i+1], list[i+2]);
/* printf("t %d %d %d\n", list[i], list[i+1], list[i+2]); */
@ -202,9 +300,9 @@ void obj_fix(char *infile, char *outfile) {
/* I start counting at one because that is how the triangle
program refers to nodes and normals */
first = 1;
ncount = 0;
vncount = 0;
fcount = 0;
ncount = 1;
vncount = 1;
fcount = 1;
printf("Reading file: %s\n", infile);
@ -361,28 +459,31 @@ void obj_fix(char *infile, char *outfile) {
refy = (ymin + ymax) / 2.0;
refz = (zmin + zmax) / 2.0;
fprintf(out, "\n");
fprintf(out, "ref %.2f %.2f %.2f\n", refx, refy, refz);
/* convert the cw_list to ccw add append to ccw_list */
fix_cw_list(cw_list, cw_list_ptr);
dump_global_bounds();
dump_nodes();
dump_normals();
dump_faces();
if ( fcount > 1 ) {
dump_faces();
}
fprintf(out, "winding ccw\n");
dump_list(ccw_list, ccw_list_ptr);
fprintf(out, "winding cw\n");
dump_list(cw_list, cw_list_ptr);
fclose(in);
fclose(out);
}
/* $Log$
/* Revision 1.12 1998/05/16 13:11:26 curt
/* Fixed an off by one error in node, normal, and face counters.
/* Revision 1.13 1998/05/20 20:55:19 curt
/* Fixed arbitrary polygon winding problem here so all tristrips are passed
/* to runtime simulator with a consistant counter clockwise winding.
/*
* Revision 1.12 1998/05/16 13:11:26 curt
* Fixed an off by one error in node, normal, and face counters.
*
* Revision 1.11 1998/04/27 15:59:24 curt
* Fixed an off by one error.
*